Summarize how a dichotomous key works

A Dichotomous key works by using a set of questions to remove choices until you get down to the one choice you are looking for. It works by :
1) a series of choices that leads to the correct name of the organism
2) at each step in using the key, the used is given two choices; each choice
    leads to another question until the item is identified

Cbecause it is the only one describing a habitat